Various types of archival microfilm recording systems are known in the prior art. The operation of these various systems is generally as follows. An image is recorded from a source in reduced (microform) size onto an intermediate or mask film, which is generally provided in the form of a film strip or roll. The intermediate film may be of the dry silver type, which produces a transparency upon development. The source can be hard copy, in which case the image is formed on the intermediate film by reflected light from the hard copy. Alternatively, the source may be a cathode ray tube or a transparency, as disclosed in U.S. Pat. No. 4,360,265 granted Nov. 23, 1982.
The latent microimage recorded on the intermediate film is developed and thereafter transferred by contact printing to an archival microform film, which usually is in the form of a microfiche film card which is a dispersion type of film. A desired frame of the microform film is imaged by flash imaging utilizing a relatively high intensity flash lamp such as a xenon flash, with the microimaged transparency functioning as a mask.
The systems of the prior art are generally constructed such that one or more of the following features are present:
(1) a single frame of the intermediate film is imaged, developed, and transferred to the archival microform film prior to imaging and/or developing the next successive frame of the intermediate film;
(2) an intermediate movable film carriage is provided that must be physically translated in order to complete an image record-image develop-image transfer cycle; and
(3) the intermediate film strip must be advanced and retracted to perform multiple image record-image develop-image transfer cycles to utilize the next available frame or area of the intermediate film.
Systems having one or more of the foregoing features can result in intermediate film fogging and cycle times which are lengthened by the time necessary to move the intermediate carriage to various stations and to retract the intermediate film.
For example, U.S. Pat. No. 3,966,317, assigned to Energy Conversion Devices, Inc., discloses a dry process method and apparatus for producing archival microform records from light reflecting hard copy. A dry-process intermediate or mask film strip which is photosensitive to and imaged by light and dry developed by heat to provide imaged transparencies therein. The dry process mask film is advanced or moved to an imaging station where light is applied to the hard copy to be reflected thereby and the light image reflected from the hard copy is reduced or condensed to microimage size and applied at the imaging station. Thereafter, the dry-process mask film is advanced or moved to the developing station where the individual exposed frame of the mask film strip is heated to develop the microimage into a microimage transparency frame. Thereafter, the microimaged transparency frame is advanced to the image transferring station for imaging transferring purposes. The image contained in the microimaged transparency frame is transferred to an archival microform film which may be in the form of a microfiche or microform card.
In accordance with the method and apparatus disclosed in U.S. Pat. No. 3,966,317, a single frame of the intermediate film is exposed, then that frame of the intermediate film advanced to development, and then that frame is advanced to the image transfer station. Thereafter, in order to utilize the next available frame or area of the film and to avoid wasting significant amounts of the intermediate film, the intermediate film must be retracted or moved such that the previously microimaged transparency frame is in a position closely spaced from the imaging point in the imaging and developing station for the next cycle of operation. There are several inherent disadvantages to such an apparatus and method. Relatively long cycle times result, since for each imaging cycle the intermediate film must be advanced to each of the imaging, developing and image transferring stations and then retracted before another frame of the intermediate film can be imaged. Another drawback has to do with the nature of the intermediate film. When an image is transferred from the intermediate film to the archival microform film, which is generally a dispersion imaging film, a relatively high intensity flash is utilized with the intermediate film acting as a mask. When a relatively high intensity flash is used to transfer the microimage to the microform film, internal reflection can occur in the intermediate film. Such internal reflection can produce latent fog in the film which could become part of the next formed image in the intermediate film when it is developed at the developing station. The fogging problem can be overcome either by providing additional spacing between adjacent frames in the intermediate film or the film can be constructed to contain a barrier which prevents propagation of internally reflected light within the intermediate film. However, each barrier utilizes a short length of the film which could otherwise be used for imaging. Suitable techniques for preventing such propagation and intermediate film so modified are set forth in U.S. Pat. No. 4,360,579. Thus, in situations where the fogging problem may be present, additional processing steps or the use of modified film or greater spacing between images is required to avoid the possibility of fogging. Such internal reflection does not occur in significant amounts during imaging of the intermediate film since a relatively low intensity of light is utilized.
Another archival microform recording system is disclosed in U.S. Pat. No. 4,344,701. The microfiche recording system disclosed therein includes a traveling film head that moves along guides from the imaging station to a developing station and then to an image transfer station, where the image on an intermediate dry silver film is to be replicated onto a positive, initially opaque microfiche film card of the photo-developing type (see U.S. Pat. No. 4,137,078, issued June 30, 1979 to Izu and Ovshinsky, for a description of the microfiche film). Provision is made for annotation of the microfiche film in which a portion of the imaging station is movable on a carriage together with a read illumination assembly which must be moved and aligned in order to read from the microfiche film.
Still another archival microform recording system is disclosed in U.S. Pat. No. 4,123,157. The system disclosed therein also records reflected light from hard copy on an intermediate or mask film, which is thereafter developed by heat. A mask film carriage is provided that contains the intermediate film, and the developing station. To record an image from hard copy, the recording head is positioned over the imaging station and a particular frame of intermediate film is microimaged. The microimaged frame is then developed by applying heat to the film from the developing station, which results in a microimaged transparency. To transfer the developed microimaged transparency, the mask film carriage is then translated or moved to the image transferring station where the developed frame of mask film is positioned in desired relation to the archival microform film or card which is carried by a movable microfiche carriage where the image is recorded by flash imaging through the mask film. To perform the next cycle, the mask film must be advanced and the mask film carriage must be translated back to the imaging station and the foregoing cycle is repeated. Thus, only a single frame of the intermediate film is imaged and developed prior to image transfer to the archival microform film. Thus, the fogging problems previously discussed with respect to U.S. Pat. No. 3,966,317 are not eliminated by the apparatus disclosed in U.S. Pat. No. 4,123,157.
Provision is also made in U.S. Pat. No. 4,123,157 for reading and annotating the microfiche film in which a read illuminator is mounted on a carriage with part of the imaging station. The carriage must be moved and aligned together with the microfiche carriage to read and annotate the microfiche film.
U.S. Pat. No. 4,332,466 discloses an apparatus for high speed recording in microform from computer or other electrical signal sources. While successive frames of intermediate film are exposed and developed, the apparatus has a developing station that partially develops at least several frames at a time. No provision is made for retraction of the intermediate film after completion of a recording cycle further causing excessive use of intermediate film. While the images are transferred to a microfiche film, no provision is made for reading and/or annotating the microfiche film.
A need exists for a microform recording apparatus which eliminates the possibility of fogging the intermediate film during image transfer to the microfiche film. A need also exists for a system which does not require translation of an intermediate film carriage to complete one or more image record-image develop-image transfer cycles. Also, a need exists for a microform recording apparatus of simplified design and operation that provides for reduced cycle times and minimizes spacing of images on the intermediate film and which avoids waste of the intermediate film. Further, a need exists for a microform recording apparatus which has the capability of reading and annotating the microfiche film that is simple in design and operation.